U.S. patent application number 15/682862 was filed with the patent office on 2019-02-28 for aircraft propulsion system and method.
The applicant listed for this patent is General Electric Company. Invention is credited to Narendra Joshi, Nikolai N. Pastouchenko, Jixian Yao, JR..
Application Number | 20190061961 15/682862 |
Document ID | / |
Family ID | 63294050 |
Filed Date | 2019-02-28 |
United States Patent
Application |
20190061961 |
Kind Code |
A1 |
Pastouchenko; Nikolai N. ;
et al. |
February 28, 2019 |
AIRCRAFT PROPULSION SYSTEM AND METHOD
Abstract
An aircraft propulsion system includes a boundary layer
ingestion (BLI) fan system disposed at an aft end of an aircraft.
The BLI fan system includes a fan that is configured to rotate
about an axial centerline of the BLI fan system in a first
direction of rotation. The BLI fan system includes blades that are
positioned at a first pitch angle configured to rotate with the
fan. An electric motor operably coupled with the BLI fan system is
configured to change a direction of rotation of the fan to a
different, second direction of rotation. An actuator operably
coupled with the BLI fan system is configured to change a position
of the blades of the fan to be positioned at a different, second
pitch angle.
Inventors: |
Pastouchenko; Nikolai N.;
(Niskayuna, NY) ; Yao, JR.; Jixian; (Niskayuna,
NY) ; Joshi; Narendra; (Niskayuna, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
63294050 |
Appl. No.: |
15/682862 |
Filed: |
August 22, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B64D 27/24 20130101;
B64C 21/06 20130101; B64C 11/30 20130101; B64D 27/08 20130101; F01D
7/00 20130101; B64D 2027/026 20130101; B64C 11/001 20130101; B64D
27/20 20130101; Y02T 50/10 20130101; Y02T 50/60 20130101; B64D
29/04 20130101; B64C 1/16 20130101 |
International
Class: |
B64D 27/08 20060101
B64D027/08; B64D 27/24 20060101 B64D027/24; B64D 29/04 20060101
B64D029/04; F01D 7/00 20060101 F01D007/00 |
Claims
1. An aircraft propulsion system comprising: a boundary layer
ingestion (BLI) fan system disposed at an aft end of an aircraft,
the BLI fan system comprising a fan configured to rotate about an
axial centerline of the BLI fan system in a first direction of
rotation, the BLI fan system comprising blades positioned at a
first pitch angle configured to rotate with the fan, wherein an
electric motor operably coupled with the BLI fan system is
configured to change a direction of rotation of the fan to a
different, second direction of rotation, and wherein an actuator
operably coupled with the BLI fan system is configured to change a
position of the blades of the fan to be positioned at a different,
second pitch angle.
2. The system of claim 1, wherein a direction of airflow configured
to flow through the BLI fan system is in a first direction when the
fan is rotating in the first direction of rotation and when the
blades are positioned at the first pitch angle, and wherein the
direction of airflow configured to flow through the BLI fan system
is in a different, second direction when the fan is rotating in the
second direction of rotation and when the blades are positioned at
the second pitch angle.
3. The system of claim 1, wherein each blade comprises a leading
edge and a trailing edge, wherein air is configured to flow through
the BLI fan system in a direction from the leading edge towards the
trailing edge.
4. The system of claim 1, wherein the electric motor comprises a
phase switch, wherein the phase switch is configured to change the
direction of rotation of the fan.
5. The system of claim 1, further comprising a pair of jet engines
suspended beneath wings of the aircraft propulsion system, and
further comprising an electric generator electrically coupled with
the jet engines, the electric motor, and the actuator, wherein the
electric generator is configured to convert rotational energy from
the jet engines to electrical energy.
6. The system of claim 1, wherein the BLI fan system is configured
to provide thrust to the aircraft propulsion system.
7. The system of claim 6, wherein the thrust provided by the BLI
fan system is configured to be one or more of forward thrust or
reverse thrust.
8. The system of claim 1, wherein the electric motor is configured
to change a speed of rotation of the fan.
9. The system of claim 1, further comprising a flare disposed at a
rear end of the BLI fan system, wherein the flare is configured to
direct airflow into the BLI fan system.
10. The system of claim 1, wherein a movement of the aircraft and a
direction of airflow configured to flow through the BLI fan system
are in the same direction when the fan is rotating in the second
direction of rotation and when the blades are positioned at the
second pitch angle.
11. A method comprising: disposing a boundary layer ingestion (BLI)
fan system at an aft end of an aircraft of an aircraft propulsion
system, the BLI fan system comprising a fan configured to rotate
about an axial centerline of the BLI fan system in a first
direction of rotation, the BLI fan system comprising blades
positioned at a first pitch angle configured to rotate with the
fan; changing a direction of rotation of the fan to a different,
second direction of rotation with an electric motor that is
operably coupled with the BLI fan system; and changing a position
of the blades of the fan to be positioned at a different, second
pitch angle with an actuator that is operably coupled with the BLI
fan system.
12. The method of claim 11, wherein a direction of airflow
configured to flow through the BLI fan system is in a first
direction when the fan is rotating in the first direction of
rotation and when the blades are positioned at the first pitch
angle, and wherein the direction of airflow configured to flow
through the BLI fan system is in a different, second direction when
the fan is rotating in the second direction of rotation and when
the blades are positioned at the second pitch angle.
13. The method of claim 11, wherein each blade comprises a leading
edge and a trailing edge, wherein air is configured to flow through
the BLI fan system in a direction from the leading edge towards the
trailing edge.
14. The method of claim 11, further comprising changing the
direction of rotation of the fan with a phase switch of the
electric motor comprises a phase switch.
15. The method of claim 11, further comprising suspending a pair of
jet engines beneath wings of the aircraft propulsion system, and
electrically coupling an electric generator with the jet engines,
the electric motor, and the actuator, wherein the electric
generator is configured to convert rotational energy from the jet
engines to electrical energy.
16. The method of claim 11, wherein the BLI fan system is
configured to provide thrust to the aircraft propulsion system.
17. The method of claim 16, wherein the thrust provided by the BLI
fan system is configured to be one or more of forward thrust or
reverse thrust.
18. The method of claim 11, further comprising changing a speed of
rotation of the fan with the electric motor.
19. The method of claim 11, wherein a movement of the aircraft and
a direction of airflow configured to flow through the BLI fan
system are in the same direction when the fan is rotating in the
second direction of rotation and when the blades are positioned at
the second pitch angle.
20. An aircraft propulsion system comprising: a boundary layer
ingestion (BLI) fan system disposed at an aft end of an aircraft,
the BLI fan system comprising a fan configured to rotate about an
axial centerline of the BLI fan system in a first direction of
rotation, the BLI fan system comprising blades positioned at a
first pitch angle configured to rotate with the fan, wherein an
electric motor operably coupled with the BLI fan system is
configured to change a direction of rotation of the fan to a
different, second direction of rotation, wherein an actuator
operably coupled with the BLI fan system is configured to change a
position of the blades of the fan to be positioned at a different,
second pitch angle, and wherein a direction of airflow configured
to flow through the BLI fan system is in a first direction when the
fan is rotating in the first direction of rotation and when the
blades are positioned at the first pitch angle, and wherein the
direction of airflow configured to flow through the BLI fan system
is in a different, second direction when the fan is rotating in the
second direction of rotation and when the blades are positioned at
the second pitch angle.
Description
FIELD
[0001] The subject matter described herein relates to propulsion
systems of aircrafts.
BACKGROUND
[0002] A conventional commercial aircraft generally includes a
fuselage, a pair of wings, and a propulsion system that provides
thrust to the aircraft. The propulsion system typically includes at
least two aircraft engines, such as turbofan jet engines. Each
turbofan jet engine is mounted to a respective wing of the
aircraft, such as in a suspended position beneath the wing,
separated from the wing and the fuselage. Such a configuration
allows for the turbofan jet engines to interact with separate,
freestream airflows that are not impacted by the wings and/or
fuselage. This configuration can reduce an amount of turbulence
within the air entering an inlet of each respective turbofan jet
engine, which has a positive effect on a net propulsive thrust of
the aircraft.
[0003] Drag on the aircraft, including the turbofan jet engines,
has an effect on the net propulsion thrust of the aircraft. A total
amount of drag on the aircraft, including skin friction and form
drag, is generally proportional to a difference between a
freestream velocity of air approaching the aircraft and an average
velocity of a wake downstream from the aircraft that is produced
due to the drag on the aircraft. Systems have been proposed to
counter the effects of drag and/or to improve an efficiency of the
turbofan jet engines. For example, certain propulsion systems
include boundary layer ingestion systems to route a portion of
relatively slow-moving air forming a boundary layer across the
fuselage and/or the wings, into the turbofan jet engines upstream
from a fan section of the turbofan jet engines. This configuration
may reenergize the boundary layer airflow downstream from the
aircraft that has a nonuniform or distorted velocity profile.
[0004] One issue with known aircraft propulsion systems is
generating and providing reverse thrust to the aircraft in order to
reduce the speed of movement of the aircraft. For example, when the
aircraft is landing, the aircraft is moving at high speeds which
puts strain on the braking system of the aircraft. Conventional
thrust reverser systems that assist the braking system in slowing
or stopping the aircraft include heavy equipment thereby adding
weight to the aircraft and reducing the fuel efficiency of the
system. Therefore, an improved system may provide improved fuel
efficiency, improve propulsive efficiency, thereby reducing
operating and maintenance costs, and improve the life of the
aircraft.
BRIEF DESCRIPTION
[0005] In one embodiment, an aircraft propulsion system includes a
boundary layer ingestion (BLI) fan system disposed at an aft end of
an aircraft. The BLI fan system includes a fan that is configured
to rotate about an axial centerline of the BLI fan system in a
first direction of rotation. The BLI fan system includes blades
that are positioned at a first pitch angle configured to rotate
with the fan. An electric motor operably coupled with the BLI fan
system is configured to change a direction of rotation of the fan
to a different, second direction of rotation. An actuator operably
coupled with the BLI fan system is configured to change a position
of the blades of the fan to be positioned at a different, second
pitch angle.
[0006] In one embodiment, a method includes disposing a boundary
layer ingestion (BLI) fan system at an aft end of an aircraft of an
aircraft propulsion system. The BLI fan system includes a fan that
is configured to rotate about an axial centerline of the BLI fan
system in a first direction of rotation. The BLI fan system
includes blades that are positioned at a first pitch angle
configured to rotate with the fan. The method also includes
changing a direction of rotation of the fan to a different, second
direction of rotation with an electric motor that is operably
coupled with the BLI fan system, and changing a position of the
blades of the fan to be positioned at a different, second pitch
angle with an actuator that is operably coupled with the BLI fan
system.
[0007] In one embodiment, an aircraft propulsion system includes a
boundary layer ingestion (BLI) fan system that is disposed at an
aft end of an aircraft. The BLI fan system includes a fan that is
configured to rotate about an axial centerline of the BLI fan
system in a first direction of rotation. The BLI fan system
includes blades that are positioned at a first pitch angle
configured to rotate with the fan. An electric motor operably
coupled with the BLI fan system is configured to change a direction
of rotation of the fan to a different, second direction of
rotation. An actuator operably coupled with the BLI fan system is
configured to change a position of the blades of the fan to be
positioned at a different, second pitch angle. A direction of
airflow configured to flow through the BLI fan system is in a first
direction when the fan is rotating in the first direction of
rotation and when the blades are positioned at the first pitch
angle, and wherein the direction of airflow configured to flow
through the BLI fan system is in a different, second direction when
the fan is rotating in the second direction of rotation and when
the blades are positioned at the second pitch angle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present inventive subject matter will be better
understood from reading the following description of non-limiting
embodiments, with reference to the attached drawings, wherein
below:
[0009] FIG. 1 illustrates a top view of an aircraft system in
accordance with one embodiment;
[0010] FIG. 2 illustrates a side view of the aircraft system of
FIG. 1 in accordance with one embodiment;
[0011] FIG. 3 illustrates a cross-sectional perspective view of a
boundary layer ingestion (BLI) fan system in accordance with one
embodiment;
[0012] FIG. 4A illustrates a partial perspective view of the BLI
fan system of FIG. 3 having blades positioned at a first pitch
angle in accordance with one embodiment;
[0013] FIG. 4B illustrates a partial front view of the BLI fan
system of FIG. 3 having blades positioned at a first pitch angle in
accordance with one embodiment;
[0014] FIG. 4C illustrates a side view of the BLI fan system of
FIGS. 4A and 4B in accordance with one embodiment;
[0015] FIG. 5A illustrates a partial perspective view of the BLI
fan system of FIG. 3 having blades positioned at a second pitch
angle in accordance with one embodiment;
[0016] FIG. 5B illustrates a partial front view of the BLI fan
system of FIG. 3 having blades positioned at a second pitch angle
in accordance with one embodiment;
[0017] FIG. 5C illustrates a side view of the BLI fan system of
FIGS. 5A and 5B in accordance with one embodiment; and
[0018] FIG. 6 illustrates a method flowchart in accordance with one
embodiment.
DETAILED DESCRIPTION
[0019] One or more embodiments of the inventive subject matter
described herein relates to systems and methods that effectively
provide thrust to an aircraft propulsion system. The systems and
methods change a direction of rotation of a fan of a boundary layer
ingestion (BLI) fan system. The systems and methods change a
position of blades of the fan with an electric motor. By changing
the direction of the rotation of the fan of the BLI fan system, and
changing the position of the blades of the BLI fan system, the
systems and methods change a direction of airflow through the BLI
fan system. The change in the direction of airflow of the BLI fan
system enables the BLI fan system to provide forward thrust as well
as reverse thrust to the aircraft propulsion system. One technical
effect of the subject matter described herein is managing the
desired amount and direction of thrust that may be provided by the
BLI fan system to the aircraft system. One technical effect of the
subject matter described herein is improved reduction of speed of
the aircraft system (e.g., slows more quickly) when the aircraft
system is landing, decelerating, or the like, thereby extending
part life of a braking system of the aircraft.
[0020] As used herein, the terms "first", "second", or "third" may
be used interchangeably to distinguish one component from another
and are not intended to signify location or importance of the
individual components. The terms "forward" and "aft" refer to the
relative positions of a component based on an actual or anticipated
direction of travel. For example, "forward" may refer to a front of
an aircraft based on an anticipated direction of travel of the
aircraft, and "aft" may refer to a back of the aircraft based on an
anticipated direction of travel of the aircraft. Additionally, the
terms "upstream" and "downstream" refer to the relative direction
with respect to fluid flow in a fluid pathway. For example,
"upstream refers to the direction from which the fluid flows, and
"downstream" refers to the direction to which the fluid flows.
[0021] FIG. 1 illustrates a top view of an aircraft system 10 in
accordance with one embodiment. FIG. 2 illustrates a side view of
the aircraft system 10 in accordance with one embodiment. FIGS. 1
and 2 will be discussed together in detail herein.
[0022] The aircraft system 10 includes an aircraft 13 having a
fuselage 12 that extends between a forward end 16 and an aft end 18
of the aircraft 13 along a longitudinal direction of the aircraft
13. The aircraft 13 defines a longitudinal centerline 14 that
extends therethrough a vertical direction V and a lateral direction
L. The aircraft 13 defines a mean line 15 that extends between the
forward end 16 and the aft end 18 of the fuselage 12. As used
herein, the term "fuselage" generally includes all of the body of
the aircraft 13, such as an empennage of the aircraft 13.
Additionally, as used herein, the "mean line" refers to a midpoint
line extending along a length of the aircraft 13, not taking into
account the appendages of the aircraft system 10 (e.g., wings 20
and stabilizers that will be discussed in more detail below).
[0023] The aircraft 13 includes a pair of wings 20. A first wing
extends laterally from a port side 22 of the fuselage 12 in the
lateral direction L, and a second wing extends laterally from a
starboard side 24 of the fuselage 12. Each of the wings 20 includes
one or more leading edge flaps 26 and one or more trailing edge
flaps 28. Optionally, the wings 20 may not include the leading edge
flaps 26 and/or the trailing edge flaps 28. The aircraft 13
includes a vertical stabilizer 30 and a pair of horizontal
stabilizers 34 at the aft end 18 of the aircraft 13. The vertical
stabilizer 30 has a rudder flap 32 for yaw control, and each of
horizontal stabilizers 34 has an elevator flap 36 for pitch control
of the aircraft system 10. The fuselage 12 includes an outer
surface or skin 38. FIGS. 1 and 2 illustrate one embodiment of the
aircraft system 10. Optionally, the aircraft system 10 may include
any alternative configuration of stabilizers, wings, or the like,
that may extend from the aircraft 13 along the vertical direction
V, the horizontal or lateral direction L, or in any alternative
direction away from the centerline 14 and/or the mean line 15.
[0024] The aircraft system 10 includes an aircraft propulsion
system 100. The aircraft propulsion system 100 includes a pair of
aircraft engines, at least one mounted to each of the pair of wings
20, and an aft engine. In the illustrated embodiment, the aircraft
propulsion system 100 engines may be configured as turbofan jet
engines 102, 104 that are suspended beneath the wings 20 in an
under-wing configuration. Additionally or alternatively, the jet
engines 102, 104 may be positioned at a different location between
the forward and aft ends 16, 18 of the aircraft 13, may be
positioned above the wings 20, or at any alternative location.
Optionally, the aircraft propulsion system 100 may include any
number and/or configuration of jet engines including non-limiting
examples of turbofans, turboprops, turbojets, or the like. For
example, the aircraft propulsion system 100 may not include
underwing mounted jet engines 102, 104, and may include any
alternative power source (e.g., an electric power source) for
powering the aircraft system 10.
[0025] The aft engine is a fan that is configured to ingest and
consume air forming a boundary layer over the fuselage 12 of the
aircraft 13. The aft engine may be referred to herein as a boundary
layer ingestion (BLI) fan system 106. The BLI fan system 106 is
mounted to the fuselage 12 at a location aft of the wings 20 and/or
the jet engines 102, 104, such that the mean line 15 extends
through the BLI fan system 106. For example, such a configuration
positions a center axis of the BLI fan system 106 above the
centerline 14 in the vertical direction V. Additionally, the BLI
fan system 106 may be mounted parallel to the centerline 14 in the
lateral direction L, or at an angle to the centerline 14. For
example, the center axis of the BLI fan system 106 may define an
angle with the centerline 14. The BLI fan system 106 is fixedly
connected to the fuselage 12 at the aft end 18 such that the BLI
fan system 106 is incorporated into or blended with a tail section
of the aircraft system 10 at the aft end 18. Optionally, the BLI
fan system 106 may be positioned in any alternative locations near
the aft end 18 of the aircraft 13.
[0026] The jet engines 102, 104 are configured to provide power to
an electric generator 108 and/or an energy storage device 110 of
the aircraft propulsion system 100. For example, one or more of the
jet engines 102, 104 may be configured to provide mechanical power
from a rotating shaft (e.g., a low-pressure shaft or high-pressure
shaft) to the electric generator 108. In the illustrated
embodiment, the jet engines 102, 104 are operably coupled with a
single electric generator 108. Optionally, the jet engines 102, 104
may be operably coupled with two or more electric generators. The
electric generator 108 may convert the rotational energy generated
by the jet engines 102, 104 into electrical energy. Additionally or
alternatively, the electric generator 108 may convert the
mechanical power to electrical power and provide the converted
electrical power to the energy storage device 110.
[0027] The aircraft propulsion system 100 includes an electric
motor 40 operably coupled with the BLI fan system 106. For example,
the electric motor 40 may electrically control one or more
operation of the BLI fan system 106. Optionally, the electric motor
40 may be operably coupled with one or more components of the BLI
fan system 106. Additionally, the electric generator 108 and/or the
energy storage device 110 are electrically coupled with the
electric motor 40. For example, the electric generator 108 may
provide converted electrical power to the electric motor 40. The
electric motor 40 may control operation of the BLI fan system 106
using the electrical power generated by the electric generator 108
and supplied to the electric motor 40.
[0028] In the illustrated embodiment, the electric generator 108,
the energy storage device 110, and the electric motor 40 are
separated from the jet engines 102, 104. Additionally or
alternatively, one or more of the electric generator 108, energy
storage device 110, or the electric motor 40 may be configured with
the jet engines 102, 104. Optionally, the aircraft propulsion
system 100 may include plural electric generators 108. Each
electric generator 108 may be operably coupled with each of the jet
engines 102, 104. Optionally, one or more of the jet engines 102,
104 may be a high bypass, turbofan jet engine with an electric
generator driven by one or more shafts of the turbofan jet
engine.
[0029] FIG. 3 illustrates a cross-sectional perspective view of the
BLI fan system 106 in accordance with one embodiment. The BLI fan
system 106 is mounted to the aircraft 13 near the aft end 18 of the
aircraft system 10. The BLI fan system 106 defines a radial
direction R and an axial direction A. The axial direction A extends
along a longitudinal, axial centerline 202 that extends through a
center of the BLI fan system 106 between a forward end 248 and a
rear end 250 of an outer nacelle 206. The outer nacelle 206
includes an inlet 220 at the forward end 248 and an outlet 230 at
the rear end 250. For example, during cruising operation of the
aircraft system 10, boundary layer air may flow into the inlet 220
at the forward end 248 and exit the BLI fan system 106 from the
outlet 230 at the rear end 250 of the outer nacelle 206. For
example, the outer nacelle 206 defines a passageway through which
air is configured to flow.
[0030] The aircraft propulsion system 100 (of FIGS. 1 and 2) also
includes an actuator 218 operably coupled with the BLI fan system
106. The actuator 218 may be a motor, a mechanical actuator, a
hydraulic actuator, a hydraulic pump, or the like. In the
illustrated embodiment, a single actuator 218 is operably coupled
with the BLI fan system 106. Additionally or alternatively, the
propulsion system 100 may have one or more actuators 218 that are
operably coupled with the BLI fan system 106. The actuator 218 is
disposed within the fuselage 12 at the aft end 18 of the aircraft
system 10. Alternatively, the actuator 218 may be disposed at an
alternative location within the aircraft system 10.
[0031] The actuator 218 electrically and/or mechanically controls
operations of the BLI fan system 106. Additionally, the electric
generator 108 and/or the energy storage device 110 are electrically
coupled with the actuator 218. For example, the electric generator
108 may provide converted electrical power to the actuator 218. The
actuator 218 may control one or more operations of the BLI fan
system 106 using the electrical power generated by the electric
generator 108 and supplied to the actuator 218.
[0032] The BLI fan system 106 includes inlet guide vanes 208 and
outlet guide vanes 222. Optionally, in one or more embodiments, the
BLI fan system 106 may be devoid of the inlet guide vanes 208
and/or devoid of the outlet guide vanes 222. Additionally or
alternatively, the inlet guide vanes 208 may be referred to as
inlet guide blades 208, and the outlet guide vanes 222 may be
referred to as outlet guide blades 222. For example, the inlet and
outlet guide blades 208, 222 may be shaped and sized similar to or
unique to the fan blades 212. The inlet guide vanes 208 are fixedly
coupled to the outer nacelle 206 and disposed near the forward end
248 of the outer nacelle 206 along the axial centerline 202. The
outlet guide vanes 222 are fixedly coupled to the outer nacelle 206
and disposed near the rear end 250 of the outer nacelle 206 along
the axial centerline 202. For example, the fan 210 is disposed
between the inlet guide vanes 208 and the outlet guide vanes 222.
Additionally or alternatively, the inlet and/or outlet guide vanes
208, 222 may be variable guide vanes. One or more of the inlet
guide vanes 208 and/or one or more of the outlet guide vanes 222
may be rotatable about a guide vane axis (not shown) corresponding
to each inlet guide vanes 208 and/or each outlet guide vanes 222.
For example, the actuator 218 may be operably coupled with the
inlet and/or outlet guide vanes 208, 222 and may provide electrical
or mechanical power in order to rotate the inlet and/or outlet
guide vanes 208, 222 from a first pitch angle to a different,
second pitch angle. Optionally, a first actuator may be operably
coupled with and control the position of the inlet guide vanes 208
and a different, second actuator may be operably coupled with and
control the position of the outlet guide vanes 222.
[0033] The inlet and outlet guide vanes 208, 222 are shaped, sized,
and oriented within the outer nacelle 206 in order to direct and/or
condition a flow of air that flows through the BLI fan system 106.
For example, the inlet and outlet guide vanes 208, 222 may increase
an efficiency of the BLI fan system 106, may reduce distortion of
air flowing into the BLI fan system 106, add strength and/or
rigidity to the BLI fan system 106, or the like, relative to a BLI
fan system 106 that is devoid inlet and/or outlet guide vanes 208,
222.
[0034] The BLI fan system 106 includes a fan 210 that includes a
rotating fan shaft 216 that is rotatable about the axial centerline
202 within the outer nacelle 206. The BLI fan system 106 includes
plural fan blades 212 that are spaced substantially uniform with
respect to each other fan blade 212 about the axial centerline 202.
In one or more embodiments, the fan blades 212 may be fixedly
attached to the fan shaft 216 or may be rotatably attached to the
fan shaft 216. For example, the fan blades 212 may be attached to
the fan shaft 216 such that a pitch angle of each of the blades 212
may be changed (e.g., in unison or not in unison) by the actuator
218 directing the blades 212 to rotate around or about a blade axis
of each of the fan blades 212. In one or more embodiments, the
pitch angle of the fan blades 212 may be changed by the actuator
218, by a hydraulic pump (not shown), or an alternative mechanism.
Changing the pitch of the plurality of fan blades 212 may increase
an efficiency of the BLI fan system 106, may allow the BLI fan
system 106 to achieve a desired thrust, or the like, relative to a
BLI fan system 106 that does not change the pitch of the fan blades
212. For example, the BLI fan system 106 may be referred to as a
variable pitch fan. The pitch angle of the fan blades 212 will be
discussed in more detail below.
[0035] The fan shaft 216 of the BLI fan system 106 is operably
coupled with the electric motor 40 (of FIGS. 1 and 2). The electric
motor 40 may change one or more of the speed of rotation of the fan
shaft 216, a direction of rotation of the fan shaft 216 of the fan
210, or the like. Changing a direction and/or speed of rotation of
the fan 210 may increase an efficiency of the aircraft propulsion
system 100, may increase an efficiency of the BLI fan system 106,
may allow the BLI fan system 106 to achieve a desired direction
and/or amount of thrust, or the like, relative to a BLI fan system
106 that does not change the speed and/or direction of rotation of
the fan 210. The direction of rotation of the fan 210 will be
discussed in more detail below.
[0036] The BLI fan system 106 includes a tail cone 224 and a nozzle
226. The nozzle 226 is disposed between the outer nacelle 206 and
the tail cone 224 at the rear end 250 of the nacelle 206. The tail
cone 224 is shaped and sized to direct the flow of air that is
flowing through the outlet 230 of the BLI fan system 106. The
nozzle 226 generates an amount of thrust from the air that is
flowing through the BLI fan system 106, and the tail cone 224 is
shaped in order to minimize an amount of drag on the BLI fan system
106. Additionally or alternatively, the tail cone 224 may have any
alternative shape and/or size, may be disposed at an alternative
position within the BLI fan system 106 (e.g., between the inlet 220
and the outlet 230), or the like.
[0037] FIG. 4A illustrates a partial perspective view of the BLI
fan system 106 having the fan blades 212 positioned at a first
pitch angle in accordance with one embodiment. FIG. 4B illustrates
a partial front view of the BLI fan system 106 having the blades
212 positioned at the first pitch angle in accordance with one
embodiment. FIG. 4C illustrates a side view of the BLI fan system
106. FIGS. 4A, 4B and 4C will be discussed in detail together.
[0038] The fan 210 and the plural fan blades 212 rotate in a first
direction of rotation 402 about the axial centerline 202 of the BLI
fan system 106. Each of the fan blades 212 has a pressure side 432
and a suction side 434 that is opposite the pressure side 432. The
pressure side 432 and the suction side 434 are interconnected by a
leading edge 430 and a trailing edge 440 that is opposite the
leading edge 430. The pressure side 432 is generally concave in
shape, and the suction side 434 is generally convex in shape
between the leading and trailing edges 430, 440. For example, the
generally concave pressure side 432 and the generally convex
suction side 434 provides an aerodynamic surface over which fluid
flows through the BLI fan system 106.
[0039] The blades 212 in the embodiment of FIGS. 4A and 4B are
positioned at a first pitch angle 436 with respect to a blade axis
214 corresponding to each blade 212. For example, the first pitch
angle 436 may be less than 90 degrees from a horizontal axis as
illustrated in FIG. 4B. For example, the first pitch angle 436 may
be defined as the angle between the horizontal axis and a blade
chord line.
[0040] Air is flowing through the BLI fan system 106 in a first
direction of airflow 404 when the blades 212 are positioned in the
first pitch angle 436 and when the fan 210 is rotating in a first
direction of rotation 402 (e.g., in a clockwise direction
illustrated in FIG. 4A) around the axial centerline 202 of the BLI
fan system 106. The flow of air in the first direction of airflow
404 flows into the inlet 220 at the forward end 248 of the outer
nacelle 206 and exits the BLI fan system 106 through the outlet 230
at the rear end 250 of the outer nacelle 206. Additionally, the
inlet guide vanes 208 and the outlet guide vanes 222 (illustrated
in FIG. 3) may be positioned at, respectively, a first inlet pitch
angle and a first outlet pitch angle (not shown) when the flow of
air is flowing in the first direction of airflow 404 through the
BLI fan system 106.
[0041] The air flowing in the first direction of airflow 404 flows
in a direction from the leading edge 430 of the blade 212 to the
trailing edge 440 of each blade 212. For example, a first relative
velocity 410 of the airflow that is moving in the first direction
of airflow 404 is configured to be directed towards the leading
edge 430 of each blade 212.
[0042] The fan blades 212 positioned at the first pitch angle 436
and the fan 210 rotating in the first direction of rotation 402
generates forward thrust 408 that propels the aircraft system 10 in
the forward direction of movement 406 of the aircraft system 10.
For example, during operation of the aircraft system 10 when the
aircraft system 10 is cruising and/or accelerating (e.g., during
take-off), the BLI fan system 106 provides forward thrust 408 to
the aircraft system 10. The BLI fan system 106 assists the jet
engines 102, 104 in moving the aircraft system 10 in the direction
of travel in the forward direction of movement 406.
[0043] FIGS. 5A, 5B, and 5C, illustrated a change to the position
of the blades 212 and change in the direction of rotation of the
fan 210. FIG. 5A illustrates a partial perspective view of the BLI
fan system 106 having the blades 212 positioned at a different,
second pitch angle in accordance with one embodiment. FIG. 5B
illustrates a partial front view of the BLI fan system 106 having
the blades 212 positioned at the second pitch angle in accordance
with one embodiment. FIG. 5C illustrates a side view of the BLI fan
system 106. FIGS. 5A, 5B and 5C will be discussed in detail
together.
[0044] The blades 212 in the embodiment of FIGS. 5A and 5B are
positioned at a different, second pitch angle 536 with respect to
the blade axis 214 corresponding to each blade 212. The actuator
218 of the aircraft propulsion system 100 may operably control the
blades 212 in order to change the position of the pitch angle of
the blades 212 from the first pitch angle 436 to the second pitch
angle 536. For example, the actuator 218 may include a switch (not
shown) or an alternative electrical or mechanical component that
electrically or mechanically controls the position of the blades
212. The switch may be manually controlled by an operator onboard
the aircraft system 10, by an operator off-board the aircraft
system 10, or may be autonomously controlled by one or more systems
of the aircraft system 10. Each blade 212 rotates (e.g., a
clockwise direction of rotation 514 illustrated in FIG. 5A) from
the position of the first pitch angle 436 to the position of the
second pitch angle 536 about each corresponding blade axis 214. For
example, the electric generator 108 (of FIG. 1) may convert the
mechanical energy from the jet engines 102, 104 to electric energy
that is used by the actuator 218 to change the position of the
blades 212. Optionally, a hydraulic pump or an alternative
mechanism may change the position of the blades 212. Optionally,
each blade 212 may rotate in a direction opposite the direction of
rotation 514 illustrated in FIG. 5A from the position of the first
pitch angle 436 to the position of the second pitch angle 536. For
example, the blades 212 may rotate in a counter-clockwise direction
of rotation.
[0045] The electric motor 40 changes the direction of rotation of
the fan 210 from the first direction of rotation 402 (e.g.,
clockwise in FIG. 4A) to a different, second direction of rotation
502 (e.g., illustrated as counter-clockwise in FIG. 5A) about the
axial centerline 202 of the BLI fan system 106. For example, the
electric motor 40 may include one or more phase switches (not
shown), or alternative electrical components, that may electrically
change the direction of rotation of the fan. The phase switch may
be manually controlled by an operator onboard the aircraft system
10, by an operator off-board the aircraft system 10, or may be
autonomously controlled by one or more systems of the aircraft
system 10. Optionally, the electric motor 40 may change the
direction of rotation of the fan 210 to the second direction of
rotation 502, and may increase and/or decrease a speed of rotation
of the fan 210. For example, the electric motor 40 may direct the
speed of the fan to decrease (e.g., to a predetermined lower fan
speed limit threshold, to a stop, or the like), then change the
direction of rotation of the fan to the second direction of
rotation 502. Optionally, the direction of rotation of the fan may
remain unchanged when the blades 212 are configured to rotate in
the counter-clockwise direction (e.g., a direction opposite the
direction of rotation 514).
[0046] Optionally, in one or more embodiments, the actuator 218 may
operably control the inlet guide vanes 208 and/or the outlet guide
vanes 222 in order to change the position of the pitch angle of the
inlet and/or outlet guide vanes 208, 222 to a different, second
pitch angle. For example, the actuator 218 may include one or more
switches (not shown) or an alternative electrical component that
electrically controls the position of the inlet and/or outlet guide
vanes 208, 222. The actuator 218 may change the position of the
inlet and outlet guide vanes 208, 222 from a first inlet pitch
angle to a different, second inlet pitch angle, and from a first
outlet pitch angle to a different, second outlet pitch angle,
respectively. For example, the inlet guide vanes 208 may have a
first inlet pitch angle that is unique to the first outlet pitch
angle of the outlet guide vanes 222 and that is unique to the first
pitch angle 436 of the fan blades 212. Additionally, the actuator
218 may change the position of the inlet guide vanes 208 to a
second inlet pitch angle that is unique to the second outlet pitch
angle of the outlet guide vanes 222 and that is unique to the
second pitch angle 536 of the fan blades 212. For example, the
actuator 218 may change the position of the inlet guide vanes 208,
the outlet guide vanes 222, and the fan blades 212 to unique and/or
common positions. Optionally, the propulsion system 100 may include
three actuators 218 that operably control the position of the inlet
guide vanes 208, the fan blades 212, and the outlet guide vanes
222. For example, a first actuator may be operably coupled with the
fan blades 212 in order to change the position of the pitch angle
of the fan blades 212, a second actuator may be operably coupled
with the inlet guide vanes 208 in order to change the position of
the pitch angle of the inlet guide vanes 208, and a third actuator
may be operably coupled with the outlet guide vanes 222 in order to
change the position of the pitch angle of the outlet guide vanes
222. Additionally or alternatively, the actuator 218 may include
three switches. For example, a first switch may be operably coupled
with the with the fan blades 212 in order to change the position of
the pitch angle of the fan blades 212, a second switch may be
operably coupled with the inlet guide vanes 208 in order to change
the position of the pitch angle of the inlet guide vanes 208, and a
third switch may be operably coupled with the outlet guide vanes
222 in order to change the position of the pitch angle of the
outlet guide vanes 222.
[0047] Changing the position of the blades 212 of the BLI fan
system 106 from the first pitch angle 436 to the second pitch angle
536, and changing the direction of rotation of the fan 210 from the
first direction of rotation 402 to the second direction of rotation
502 changes a direction of flow of air through the BLI fan system
106 from the first direction of airflow 404 to a different, second
direction of airflow 504. The flow of air in the second direction
of airflow 504 flows into the outlet 230 at the rear end 250 of the
outer nacelle 206 and exits the BLI fan system 106 through the
inlet 220 at the forward end 248 of the outer nacelle 206.
[0048] The air flowing in the second direction of airflow 504 flows
in a direction from the leading edge 430 of the blade 212 to the
trailing edge 440 of each blade 212. For example, a second relative
velocity 510 of the airflow that is moving in the second direction
of airflow 504 is configured to be directed towards the leading
edge 430 of each blade 212.
[0049] The fan blades 212 positioned at the second pitch angle 536
and the fan 210 rotating in the second direction of rotation 502
generates reverse thrust 508 that counteracts the propulsion of the
aircraft system 10 in the forward direction of movement 406 of the
aircraft system 10. For example, during operation of the aircraft
system 10 when the aircraft system 10 is landing, the BLI fan
system 106 provides reverse thrust 508 to the aircraft system 10.
The BLI fan system 106 assists a braking system (not shown) of the
aircraft system 10 by slowing, reducing, or stopping the forward
direction of movement 406 of the aircraft system 10.
[0050] As illustrated in FIG. 4C, when the fan 210 is rotating in
the first direction of rotation 402, the blades are positioned at
the first pitch angle 436, and air is flowing through the BLI fan
system 106 in the first direction of airflow 404, the first
direction of airflow 404 through the BLI fan system 106 is in an
opposite direction as the direction of movement 406 of the aircraft
system 10. Alternatively, as illustrated in FIG. 5C, when the fan
210 is rotating in the second direction of rotation 502, the blades
are positioned at the second pitch angle 536, and air is flowing
through the BLI fan system 106 in the second direction of airflow
504, the second direction of airflow 504 through the BLI fan system
106 is in the same direction as the direction of movement 406 of
the aircraft system 10. Optionally, the inlet guide vanes 208 and
the outlet guide vanes 222 may be positioned at, respectively, a
first inlet pitch angle and a first outlet pitch angle (e.g., a
first inlet pitch angle that may be the same or different than the
first pitch angle 436, and a first outlet pitch angle that may be
the same or different than the first pitch angle 436) when the flow
of air is flowing in the first direction of airflow 404 through the
BLI fan system 106, and the inlet and outlet guide vanes 208, 222
may be positioned at, respectively, a different, second inlet pitch
angle and different, second outlet pitch angle (e.g., a second
inlet pitch angle that may be the same or different than the second
pitch angle 536, and a second outlet pitch angle that may be the
same or different than the second pitch angle 536) when the flow of
air is flowing in the second direction of airflow 504 through the
BLI fan system 106.
[0051] In one or more embodiments, the BLI fan system 106 includes
a flare 420 that is disposed at the rear end 250 of the outer
nacelle 206. The flare 420 extends around a perimeter of the outer
nacelle 206. The flare 420 is shaped and sized in order to direct
the flow of air flowing in the second direction of airflow 504 into
the outlet 230 of the BLI fan system 106. For example, the flare
420 includes an inner flare surface 422 that is disposed near the
outlet 230 of the outer nacelle 206, and an outer flare surface 424
that is disposed distal to the outer nacelle 206 relative to the
inner flare surface 422. The outer flare surface 424 has a diameter
that is larger than a diameter of the inner flare surface 422. For
example, the flare 420 may direct non-boundary layer air into the
outlet 230 of the BLI fan system 106 when the BLI fan system 106 is
providing reverse thrust (e.g., reverse thrust 508) to the aircraft
system 10.
[0052] FIG. 6 illustrates a flowchart of one embodiment of a method
600 for providing a propulsion system of an aircraft. At 602, a
boundary layer ingestion (BLI) fan system (e.g., BLI fan system
106) is disposed at an aft end of an aircraft system. The BLI fan
system includes a fan 210 that includes plural blades 212. The fan
210 with blades 212 rotate about an axial centerline 202 of the BLI
fan system 106. The BLI fan system 106 consumes or ingests boundary
layer air of the aircraft system 10. Additionally or alternatively,
the BLI fan system 106 may be disposed at an alternative location
of an aircraft system and may consume or ingest freestream air or
air that has not been distorted by a fuselage, wings, or the like,
of the aircraft system. The BLI fan system 106 provides forward and
reverse thrust to the aircraft system 10. For example, the BLI fan
system 106 may provide forward thrust (e.g., forward thrust 408 of
FIG. 4C) to the aircraft system 10 when the aircraft system 10 is
taking off, cruising, or accelerating, or the like, and the BLI fan
system 106 may provide reverse thrust (e.g., reverse thrust 508 of
FIG. 5C) to the aircraft system 10 when the aircraft system 10 is
landing, decelerating, or the like.
[0053] At 604, an electric motor 40 is operably coupled with the
BLI fan system 106. For example, the electric motor 40 may be
disposed at a position within the fuselage 12 of the aircraft
system 10, and may be electrically coupled with the BLI fan system
106. Additionally, an actuator 218 is operably coupled with the BLI
fan system 106. For example, the actuator 218 may be disposed at a
position within the fuselage 12 of the aircraft system 10, and may
be electrically coupled with the BLI fan system 106. In one or more
embodiments, the electric motor 40 and the actuator 218 may receive
electrical energy from an electric generator 108, from an energy
storage device 110, or the like. For example, the electric
generator 108 may convert mechanical energy from the jet engines
102, 104 into electrical energy that may be utilized by the
electric motor 40 and/or the actuator 218. Optionally, the electric
motor 40 and/or the actuator 218 may receive electrical energy from
any alternative power source such as an electric battery or the
like. Additionally or alternatively, an electric battery may
provide power to the aircraft during take-off, may provide power to
the electric motor, or the like. In one or more embodiments, the
propulsion system 100 may include numerous electric motors 40,
actuators 218, hydraulic pumps, or any alternative power source,
operably coupled with the BLI fan system 106.
[0054] At 606, the electric motor 40 changes a direction of
rotation of the fan 210 from the first direction of rotation 402 to
the different, second direction of rotation 502. For example, the
electric motor 40 may include a phase switch, or any alternative
component that may change the direction of rotation of the fan 210.
The electric motor 40 controls the direction of rotation of the fan
210. For example, the electric motor 40 may reduce the speed of the
rotation of the fan 210 as the fan 210 rotates in the first
direction of rotation 402 until the speed of the rotation of the
fan 210 has reached a predetermined threshold, has come to a stop,
or the like. The phase switch changes a phase of the electric motor
40 in order to change the direction of rotation of the fan 210 to
the second direction of rotation 502. The electric motor 40 may
increase or decrease the speed of the rotation of the fan 210
rotating in the first direction or rotation 402 or the second
direction of rotation 502 until the speed of the rotation of the
fan 210 has reached a desired operating speed. The fan 210 rotating
in the first direction of rotation 402 provides forward thrust 408
to the aircraft system 10. The fan 210 rotating in the second
direction of rotation 502 provides reverse thrust 508 to the
aircraft system 10.
[0055] At 608, the actuator 218 changes a position of the blades
212 of the BLI fan system 106 from the first pitch angle 436 to the
different, second pitch angle 536. For example, the actuator 218
directs the blades 212 to rotate to the second pitch angle 536
position about the corresponding blade axis 214 of each blade 212.
Optionally, the position of the blades 212 of the BLI fan system
106 may change from the first pitch angle 436 to and/or from the
second pitch angle 536 by mechanical actuators, hydraulic
actuators, or the like. The blades 212 positioned in the first
pitch angle 436 provides forward thrust 408 to the aircraft system
10. The blades 212 positioned in the second pitch angle 536
provides reverse thrust 508 to the aircraft system 10.
[0056] Optionally, the actuator 218 may change a position of the
inlet guide vanes 208 and/or the outlet guide vanes 222. For
example, the actuator 218 may change a position of the inlet guide
vanes 208 from a first inlet pitch angle to the different, second
inlet pitch angle by directing the inlet guide vanes 208 to rotate
to the second inlet pitch angle about a corresponding vane axis
(not shown) of each inlet guide vane 208. Additionally, the
actuator 218 may change a position of the outlet guide from a first
outlet pitch angle to the different, second outlet pitch angle by
directing the outlet guide vanes 222 to rotate to the second outlet
pitch angle about a corresponding vane axis (not shown) of each
outlet guide vane 222.
[0057] In one or more embodiments, the electric motor 40 may change
one or more of the direction or speed of rotation of the fan 210
from the first direction of rotation 402 to the second direction of
rotation 502, but the actuator 218 may not change the position of
the blades 212. Additionally or alternatively, the actuator 218 may
change the position of the blades 212 from the first pitch angle
436 to the second pitch angle 536, but the electric motor 40 may
not change the direction and/or speed of rotation of the fan 210.
Optionally, in one or more embodiments, the pitch angle of the
outlet guide vanes and/or the inlet guide vanes may be changed
to/from a forward thrust mode of operation to a reverse thrust mode
of operation. Optionally, the propulsion system 100 may include
multiple BLI fan systems 106. For example, the multiple BLI fan
systems 106 may control different components or systems in order to
work together to provide forward thrust or reverse thrust for the
aircraft system 10. One or more of the multiple BLI fan systems 106
may change one or more of the direction of rotation of the fan 210
or the position of the blades 212. For example, a first BLI fan
system 106 may change only the direction of rotation and the speed
of rotation of the fan 210, and a second BLI fan system 106 may
change the position of the blades 212. Optionally, the one or more
BLI fan system 106 may have any uniform or unique combination of
changes to the rotation of the fan 210 and/or the position of the
blades 212.
[0058] In the illustrated embodiments, the propulsion system 100 is
used to provide propulsion to an aircraft system. Additionally or
alternatively, the propulsion system 100 may be used to provide
propulsion to any alternative system, non-limiting examples include
water systems, vehicle systems, clean energy systems, or the
like.
[0059] In one embodiment of the subject matter described herein, an
aircraft propulsion system includes a boundary layer ingestion
(BLI) fan system disposed at an aft end of an aircraft. The BLI fan
system includes a fan that is configured to rotate about an axial
centerline of the BLI fan system in a first direction of rotation.
The BLI fan system includes blades that are positioned at a first
pitch angle configured to rotate with the fan. An electric motor
operably coupled with the BLI fan system is configured to change a
direction of rotation of the fan to a different, second direction
of rotation. An actuator operably coupled with the BLI fan system
is configured to change a position of the blades of the fan to be
positioned at a different, second pitch angle.
[0060] Optionally, a direction of airflow configured to flow
through the BLI fan system is in a first direction when the fan is
rotating in the first direction of rotation and when the blades are
positioned at the first pitch angle, and wherein the direction of
airflow configured to flow through the BLI fan system is in a
different, second direction when the fan is rotating in the second
direction of rotation and when the blades are positioned at the
second pitch angle.
[0061] Optionally, each blade includes a leading edge and a
trailing edge, wherein air is configured to flow through the BLI
fan system in a direction from the leading edge towards the
trailing edge.
[0062] Optionally, the electric motor includes a phase switch,
wherein the phase switch is configured to change the direction of
rotation of the fan.
[0063] Optionally, the system includes a pair of jet engines
suspended beneath wings of the aircraft propulsion system, and
further comprises an electric generator electrically coupled with
the jet engines, the electric motor, and the actuator, wherein the
electric generator is configured to convert rotational energy from
the jet engines to electrical energy.
[0064] Optionally, the BLI fan system is configured to provide
thrust to the aircraft propulsion system. Optionally, the thrust
provided by the BLI fan system is configured to be one or more of
forward thrust or reverse thrust.
[0065] Optionally, the electric motor is configured to change a
speed of rotation of the fan.
[0066] Optionally, the system includes a flare disposed at a rear
end of the BLI fan system, wherein the flare is configured to
direct airflow into the BLI fan system.
[0067] Optionally, a movement of the aircraft and a direction of
airflow configured to flow through the BLI fan system are in the
same direction when the fan is rotating in the second direction of
rotation and when the blades are positioned at the second pitch
angle.
[0068] In one embodiment of the subject matter described herein, a
method includes disposing a boundary layer ingestion (BLI) fan
system at an aft end of an aircraft of an aircraft propulsion
system. The BLI fan system includes a fan that is configured to
rotate about an axial centerline of the BLI fan system in a first
direction of rotation. The BLI fan system includes blades that are
positioned at a first pitch angle configured to rotate with the
fan. The method also includes changing a direction of rotation of
the fan to a different, second direction of rotation with an
electric motor that is operably coupled with the BLI fan system,
and changing a position of the blades of the fan to be positioned
at a different, second pitch angle with an actuator that is
operably coupled with the BLI fan system.
[0069] Optionally, a direction of airflow configured to flow
through the BLI fan system is in a first direction when the fan is
rotating in the first direction of rotation and when the blades are
positioned at the first pitch angle, and wherein the direction of
airflow configured to flow through the BLI fan system is in a
different, second direction when the fan is rotating in the second
direction of rotation and when the blades are positioned at the
second pitch angle.
[0070] Optionally, each blade includes a leading edge and a
trailing edge, wherein air is configured to flow through the BLI
fan system in a direction from the leading edge towards the
trailing edge.
[0071] Optionally, the method further includes changing the
direction of rotation of the fan with a phase switch of the
electric motor.
[0072] Optionally, the method further includes suspending a pair of
jet engines beneath wings of the aircraft propulsion system and
electrically coupling an electric generator with the jet engines,
the electric motor, and the actuator, wherein the electric
generator is configured to convert rotational energy from the jet
engines to electrical energy.
[0073] Optionally, the BLI fan system is configured to provide
thrust to the aircraft propulsion system. Optionally, the thrust
provided by the BLI fan system is configured to be one or more of
forward thrust or reverse thrust.
[0074] Optionally, the method further includes changing a speed of
rotation of the fan with the electric motor.
[0075] Optionally, the method further includes disposing a flare at
a rear end of the BLI fan system, wherein the flare is configured
to direct airflow into the BLI fan system.
[0076] Optionally, a movement of the aircraft and a direction of
airflow configured to flow through the BLI fan system are in the
same direction when the fan is rotating in the second direction of
rotation and when the blades are positioned at the second pitch
angle.
[0077] In one embodiment of the subject matter described herein, an
aircraft propulsion system includes a boundary layer ingestion
(BLI) fan system that is disposed at an aft end of an aircraft. The
BLI fan system includes a fan that is configured to rotate about an
axial centerline of the BLI fan system in a first direction of
rotation. The BLI fan system includes blades that are positioned at
a first pitch angle configured to rotate with the fan. An electric
motor operably coupled with the BLI fan system is configured to
change a direction of rotation of the fan to a different, second
direction of rotation, and an actuator operably coupled with the
BLI fan system is configured to change a position of the blades of
the fan to be positioned at a different, second pitch angle. A
direction of airflow configured to flow through the BLI fan system
is in a first direction when the fan is rotating in the first
direction of rotation and when the blades are positioned at the
first pitch angle, and wherein the direction of airflow configured
to flow through the BLI fan system is in a different, second
direction when the fan is rotating in the second direction of
rotation and when the blades are positioned at the second pitch
angle.
[0078] As used herein, an element or step recited in the singular
and proceeded with the word "a" or "an" should be understood as not
excluding plural of said elements or steps, unless such exclusion
is explicitly stated. Furthermore, references to "one embodiment"
of the presently described subject matter are not intended to be
interpreted as excluding the existence of additional embodiments
that also incorporate the recited features. Moreover, unless
explicitly stated to the contrary, embodiments "comprising" or
"having" an element or a plurality of elements having a particular
property may include additional such elements not having that
property.
[0079] It is to be understood that the above description is
intended to be illustrative, and not restrictive. For example, the
above-described embodiments (and/or aspects thereof) may be used in
combination with each other. In addition, many modifications may be
made to adapt a particular situation or material to the teachings
of the subject matter set forth herein without departing from its
scope. While the dimensions and types of materials described herein
are intended to define the parameters of the disclosed subject
matter, they are by no means limiting and are exemplary
embodiments. Many other embodiments will be apparent to those of
skill in the art upon reviewing the above description. The scope of
the subject matter described herein should, therefore, be
determined with reference to the appended claims, along with the
full scope of equivalents to which such claims are entitled. In the
appended claims, the terms "including" and "in which" are used as
the plain-English equivalents of the respective terms "comprising"
and "wherein." Moreover, in the following claims, the terms
"first," "second," and "third," etc. are used merely as labels, and
are not intended to impose numerical requirements on their objects.
Further, the limitations of the following claims are not written in
means-plus-function format and are not intended to be interpreted
based on 35 U.S.C. .sctn. 112(f), unless and until such claim
limitations expressly use the phrase "means for" followed by a
statement of function void of further structure.
[0080] This written description uses examples to disclose several
embodiments of the subject matter set forth herein, including the
best mode, and also to enable a person of ordinary skill in the art
to practice the embodiments of disclosed subject matter, including
making and using the devices or systems and performing the methods.
The patentable scope of the subject matter described herein is
defined by the claims, and may include other examples that occur to
those of ordinary skill in the art. Such other examples are
intended to be within the scope of the claims if they have
structural elements that do not differ from the literal language of
the claims, or if they include equivalent structural elements with
insubstantial differences from the literal languages of the
claims.
* * * * *